Many wines are ruined by too much exposure to the air. Wine contains enzymes that when exposed to air, cause oxidative compounds such as phenols to react negatively. This can affect the colour, flavours and aroma, which can turn the wine brown, cause flavour loss, and even lead to a vinegary smell and taste.
Oxidization of Wine with Fermenter System
The Home Vintner uses a closed fermenter system, which includes a tight seal on the primary with a bung and airlock. This minimizes the loss of low weight molecular compounds, allows for better essence recovery, and maintains more aromatics and flavours. Be careful when transferring the wine from the primary to the carboy not to splash the wine. The hose should be as far down into the carboy as possible.
The carboy should be filled above the shoulder, but 3- 5 inches below the top. Top up if necessary. Do not store your carboys above normal room temperature and keep away from light.
Finally, use a bottle filler when bottling to minimize splashing and to allow for the correct amount of space between the wine and the bottom of the cork. Just remember the oxidization of wine is a very important part of the process.